This paper uses available evidence to determine the probable order of magnitude of fuel savings accrued from a reduction in speed limits on motorways. It is argued that the main impact of speed restrictions will be felt on rural motorways where traffic is essentially free-flowing. Fuel savings from reduced speeds would occur on cars only because commercial vehicles already have a lower speed limit (60 mile/h on motorways) and a reduction would have less effect. Using data on the distribution of car engine sizes and the speed distribution on motorways, the author is able to estimate the average fuel consumption as a function of speed. Results from a study on the effect of reducing speed limits from 70 mile/h to 50 mile/h are used to predict possible fuel savings. Although 127000 tons of petrol per year would be saved by introducing a 60 mile/h speed limit and 237000 tons would be saved per year by a 50 mile/h speed limit, these savings only represent 0.5 per cent, or 1 per cent of the total fuel consumption of road vehicles. It is concluded that this level of savings is unlikely to balance the additional cost of enforcement. (TRRL)

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • LEAKE, G R
  • Publication Date: 1980-11

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00334992
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: HS-031 192
  • Files: HSL, ITRD, TRIS
  • Created Date: Sep 16 1983 12:00AM